Containers, example, glass and plastic containers, often include a base, a finish, and a body extending therebetween. The container finish, in turn, includes a sealing surface to which a removable foil liner may be secured and sealed in order to seal the container. One technique or process that may be used to secure and seal the foil liner to the container sealing surface of the container is a conduction sealing process. In such a process, the foil liner and the sealing surface are heated by a seal head to create an acceptable bond therebetween. Another technique or process that may be used is an induction sealing process. In such a process, the foil liner and the sealing surface are heated as a result of an electromagnetic field that is generated by an induction coil in a sealing head, and an acceptable bond is formed between the foil liner and sealing surface of the container as a result of the heating therebetween. During such processes, however, the generated heat and/or the heat from a hot-filled product within the container may cause the head space of the container (i.e., the area between the contents of the container and the foil liner) to expand and/or the pressure therein to increase, thereby possibly stretching the foil liner causing it to tear or deform resulting in the formation of wrinkles in the foil liner which may detrimentally affect the seal. To account for the head space expansion and/or pressure increase, some containers, for example, certain plastic containers, may include panels sometimes referred to as vacuum panels that are designed to expand as the head space expands and/or the pressure therein increases during the application of heat, and then contract as the head space/pressure decreases following the removal of heat. However, for a container having a relatively rigid structure (e.g., a glass container) that does not allow for such expansion and contraction, the only direction the pressure in the head space can go is up towards the foil liner and, as a result, wrinkles and/or tears may form that create escape paths for the pressure and that detrimentally affect the seal.
A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide an apparatus and method for sealing that will prevent, or at least minimize, the formation of wrinkles or tears in the foil liner as a result of the sealing of the foil liner to a sealing surface of a container.
The present disclosure embodies a number of aspects that can be implemented separately from, or in combination with, each other.
An apparatus for sealing a foil liner to a sealing surface of a container, in accordance with one aspect of the disclosure, comprises a seal head that includes a body having a first end, a second end opposite the first end, an axis extending through the first and second ends, and an axially-facing sealing surface at the second end of the body facing away from the first end thereof. The seal head further includes one or more fluid paths therein for passing fluid through and out of the seal head and onto at least a portion of the foil liner.
In accordance with another aspect of the disclosure, there is provided an apparatus for sealing a foil liner to a sealing surface of a container comprising a seal head that includes a body having a first end, a second end opposite the first end, an axis extending through the first and second ends, and an axially-facing sealing surface at the second end of the body facing away from the first end thereof. The seal head further comprises a recess in the body at the second end thereof disposed radially-inward of the axially-facing sealing surface, and an inlet passageway and outlet passageway both of which extend through the body and are in fluid communication with the recess. Together, the inlet passageway, outlet passageway, and recess define a fluid path in the seal head for passing fluid through and out of the seal head and onto the foil liner. The seal head still further comprises a facing carried by the body of the seal head and disposed adjacent to the axially-facing sealing surface of the seal head body.
In accordance with a further aspect of the disclosure, there is provided an apparatus for sealing a foil liner to a sealing surface of a container comprising a seal head that includes a body having a first end, a second end opposite the first end, an axis extending through the first and second ends, and an axially-facing sealing surface at the second end of the body facing away from the first end thereof. The seal head further includes an inlet passageway, one or more outlet passageways extending at least partially in an axial direction, and one or more fluid pathways in fluid communication with the inlet passageway and the outlet passageway(s). Together the inlet passageway, outlet passageway(s), and fluid pathway(s) define a fluid path in the seal head for passing fluid through and out of the seal head and onto the foil liner.
In accordance with still a further aspect of the disclosure, there is provided a method of sealing a foil liner to a sealing surface of a container. The method comprises aligning a sealing surface of a seal head with the sealing surface of the container, wherein at least a peripheral edge of the foil liner is disposed between the sealing surfaces of the seal head and container. The method further comprises passing fluid through a fluid path in the seal head and onto the foil liner.